WO2020133239A1

WO2020133239A1 - Photovoltaic direct current breaking device

Info

Publication number: WO2020133239A1
Application number: PCT/CN2018/124961
Authority: WO
Inventors: 王勋; 张彦忠
Original assignee: 华为技术有限公司
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2020-07-02
Also published as: CN111837307B; EP3893348B1; AU2018455569B2; AU2018455569A1; US20210328546A1; EP3893348A4; CN111837307A; US11539326B2; EP3893348A1

Abstract

Disclosed in the present application is a photovoltaic direct current breaking device, capable of comprising a positive connection terminal and a negative connection terminal used to connect a photovoltaic string and a photovoltaic energy converter, and a first diode, a first switch, a converter circuit and an energy absorbing loop, the first switch, the converter circuit and the energy absorbing loop being connected in parallel, the converter circuit being capable of effectively preventing arcing and ablation when the first switch opens and closes a direct current circuit between the photovoltaic string and the photovoltaic energy converter. The first diode can effectively bypass energy stored by an energy storage device in the photovoltaic energy converter, thereby helping lower semiconductor specifications in the converter circuit. The energy absorbing loop can also effectively lower semiconductor and varistor specifications.

Description

Photovoltaic DC breaking device

Technical field

The present application relates to the field of circuit technology, and in particular to a photovoltaic DC breaking device.

Background technique

At present, large-scale photovoltaic power plants generally connect photovoltaic energy converters by connecting photovoltaic modules in series to form photovoltaic strings, such as inverters, to perform power conversion for power generation. Usually the DC voltage of the photovoltaic string reaches several hundred volts, or thousands of volts. Considering the failure or maintenance of the photovoltaic energy converter, it is necessary to reliably and quickly cut off the electrical connection between the photovoltaic string and the photovoltaic energy converter. Nowadays, a DC circuit breaker is usually used to cut off between the photovoltaic string and the photovoltaic energy converter Electrical connection. Because there is no zero-crossing point in DC and the voltage is high, the arc is easy to be generated during the cutting process and it is not easy to extinguish. There is a problem of arc ablation at the breaking contact.

In order to solve the problem of easy arcing during the DC circuit breaker cutting process, as shown in FIG. 1 in the prior art, a shunt circuit and a varistor breaking device are connected in parallel at both ends of the switch S for cutting the above electrical connection. The shunt circuit uses a semiconductor design, such as through the Q1 and Q2 two insulated gate bipolar transistors (insulated gate bipolar transistor, IGBT) in series. When the breaking device needs to be connected, first open the Q1, Q2 semiconductor tubes through the shunt circuit to achieve high-voltage turn-on, because the conduction voltage drop of the Q1, Q2 tubes is only about 1-2V, then the switch S draws in, due to the DC contact The voltage at both ends is equal to the conduction voltage drop of the shunt circuit, which is only 1-2V. At this time, the switch S attracting the contact will not cause arc drawing, contact ablation and other problems. When the breaking device needs to be opened, the switch S is opened first at this time, because the voltage across the DC contact is equal to the conduction voltage drop of the shunt circuit, only 1-2V, at this time the switch S opens the contact will not cause arcing , Contact ablation and other problems, when the switch S contact opening distance is large enough, then turn off the two IGBT Q1, Q2, to achieve the disconnection of the breaking device.

Considering the influence of the parasitic inductance of the line, during the IGBT turn-off process, voltage spikes are likely to occur, resulting in damage to the IGBT. Therefore, a varistor X is connected in parallel at both ends of the IGBT to absorb the voltage spike during turn-off and protect the IGBT. The breaking device uses a varistor X as an energy absorption device, because the DC voltage of a photovoltaic string usually has several hundred volts to thousands of amplitudes. Taking the breaking DC voltage as 1000V-10A as an example, the varistor withstand voltage needs If it is greater than 1000V, the general specification needs to be selected to 1100V, and the cost is high. Without considering the influence of the inductance on the DC/DC circuit of the inverter, only the problem of parasitic inductance of the line is considered. When the IGBT is turned off, its varistor clamping voltage will far exceed 1500V. At this time, the IGBT and the parallel diode are resistant The voltage specification needs to be selected above 1500V, the cost is higher, and the output voltage of the photovoltaic string is greatly affected by the light. Once the output voltage of the photovoltaic string is higher than the range that the varistor can withstand, it will cause damage to the sub-resistor , Thereby reducing the reliability of the breaking device.

Summary of the invention

The embodiments of the present application provide a photovoltaic DC breaking device, which can break the electrical connection between a photovoltaic string and a photovoltaic energy converter at low cost and high reliability.

The first aspect of the present application provides a photovoltaic DC breaking device, including:

The first positive connection terminal, the first negative connection terminal, the second positive connection terminal, the second negative connection terminal, the first switch, the first diode, the converter circuit and the energy absorption circuit;

Wherein, the first positive connection end and the first negative connection end are used to connect the output end of the first photovoltaic string, and the second positive connection end and the second negative connection end are used to connect the photovoltaic energy converter;

The first switch, the converter circuit, and the energy absorption circuit are connected in parallel and connected between the first negative connection terminal and the second negative connection terminal. The cathode is connected between the first positive terminal and the second positive terminal, and the anode of the first diode is connected to the first switch, the inverter circuit and the energy absorption circuit. Between the parallel circuit and the second negative connection; or, the first switch, the converter circuit, and the energy absorption circuit are connected in parallel between the first positive connection and the second Between the positive connection terminals, the cathode of the first diode is connected between the parallel circuit of the first switch, the inverter circuit, and the energy absorption circuit and the second positive connection terminal. An anode of the first diode is connected between the first negative connection terminal and the second negative connection terminal;

The commutation circuit includes a first fully controlled semiconductor device, a second fully controlled semiconductor device, a second diode, and a third diode, wherein the cathode of the second diode is connected to the input terminal of the first fully controlled semiconductor device , The anode of the second diode is connected to the output of the first fully controlled semiconductor device and the output of the second fully controlled semiconductor device, the anode of the third diode is connected to the output of the second fully controlled semiconductor device, The cathode of the three diodes is connected to the input end of the second fully controlled semiconductor device;

The energy absorption circuit includes a gas discharge tube, a varistor, and a steady-state balancing resistance, where the gas discharge tube and the steady-state balancing resistance are connected in parallel, and then connected in series with the varistor.

The first switch may be any device or combination of a relay, a circuit breaker, a contactor, and an electromagnetic mechanical switch.

The gas discharge tube G can also be replaced with a transient suppression diode.

The first diode D1 to the fourth diode D4 may also be the same type of diode or different types of diodes.

The first photovoltaic string may be a combination of photovoltaic module strings/parallel.

In the solution provided in the first aspect of the present application, when the first switch needs to be closed, the first fully-controlled semiconductor device and the second fully-controlled semiconductor device are first turned on, so that the voltage across the first switch is only about 1-2V, At this time, if the first switch is closed, the first switch K1 will not cause arc drawing and electric shock ablation, thereby increasing the service life of the first switch. When it is necessary to turn off the first switch, first control the first switch to turn off, so that the breaking voltage of the first switch is reduced to only 1-2V of the conduction voltage drop of the semiconductor device of the converter circuit 10, thereby effectively avoiding arc drawing And electric shock ablation, effectively protect the first switch K1, it is precisely because the scheme of this application can effectively protect the first switch, so when choosing the first switch, you can choose low-voltage switch specification devices, economically Can reduce the cost of photovoltaic DC disconnection device. In addition, when the first switch is opened, due to the line parasitic inductance of the photovoltaic string cable and the energy stored in the DC-to-DC circuit inductance of the photovoltaic energy converter, the first diode can be used in the embodiments of the present application. The energy stored in the DC-to-DC circuit inductance of the photovoltaic energy converter takes the bus capacitance to the first diode and returns to the path of the energy release from the DC-to-DC circuit inductance, which reduces the energy absorbed by the energy absorption circuit in the photovoltaic DC disconnection device Energy can reduce the design specifications of the energy absorption circuit.

With reference to the first aspect, in a first possible implementation manner, the photovoltaic DC disconnection device further includes a second switch;

In the case where the first switch, the converter circuit, and the energy absorption circuit are connected in parallel and connected between the first negative connection terminal and the second negative connection terminal, one end of the second switch is connected to the first negative connection terminal. The other end of the two switches is connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube, or one end of the second switch is connected to the second negative connection and the anode of the first diode, The other end of the second switch is connected to one end of the first switch, the cathode of the third diode and one end of the varistor.

It can be known from the first possible implementation manner of the first aspect above that the second switch is opened after the first switch, the converter circuit has been opened at this time, the energy absorption circuit has high resistance, and the second switch has no voltage and Current, so the second switch can use low-voltage specification switching devices to achieve a reliable disconnection approved by safety regulations.

With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner, the photovoltaic DC disconnection device further includes a third switch; the third switch is connected between the first positive connection end and the second positive Between the connection terminal and the connection point of the cathode of the first diode.

It can be known from the second possible implementation manner of the first aspect above that the third switch is opened after the first switch, at this time the converter circuit has been opened, the energy absorption circuit has high resistance, and the third switch has no voltage and Current, so the third switch can use low-voltage specification switching devices to achieve a reliable disconnection approved by safety regulations.

With reference to the first aspect, in a third possible implementation manner, the photovoltaic DC disconnection device further includes a fourth switch;

When the first switch, the inverter circuit, and the energy absorption circuit are connected in parallel and connected between the first positive connection terminal and the second positive connection terminal, one end of the fourth switch is connected to the first positive connection terminal, and the fourth switch The other end is connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube, or one end of the fourth switch is connected to the second positive connection terminal and the cathode of the first diode, the fourth The other end of the switch is connected to one end of the first switch, the cathode of the third diode and one end of the varistor.

It can be known from the third possible implementation manner of the first aspect above that the fourth switch is opened after the first switch, the converter circuit has been opened at this time, the energy absorption circuit has high resistance, and the fourth switch has no voltage and Current, so the fourth switch can use low-voltage specification switching devices to achieve a reliable disconnection approved by safety regulations.

With reference to the first aspect or the third possible implementation manner of the first aspect, in a fourth possible implementation manner, the photovoltaic DC disconnection device further includes a fifth switch; the fifth switch is connected between the first negative connection terminal and the second negative Between the connection terminal and the connection point of the anode of the first diode.

It can be known from the fourth possible implementation manner of the first aspect above that the fifth switch is turned off after the first switch, at this time, the converter circuit has been opened, the energy absorption circuit has high resistance, and the fifth switch has no voltage and Current, so the fifth switch can use low-voltage specification switching devices to achieve a reliable disconnection approved by safety regulations.

With reference to the first aspect, in a fifth possible implementation manner, the photovoltaic DC disconnection device further includes a third positive terminal and a third negative terminal; the third negative terminal is connected to the first negative terminal and the first switch, Between the three parallel circuits of the inverter circuit and the energy absorption circuit, the third positive connection terminal is connected between the first positive connection terminal and the second positive connection terminal and the connection point of the cathode of the first diode, and the third positive connection The terminal and the third negative connecting terminal are used to connect the input terminal of the second photovoltaic string.

It can be known from the fifth possible implementation manner of the first aspect above that the photovoltaic DC breaking device can control the electrical connection between a plurality of photovoltaic strings and a photovoltaic energy converter, thereby improving the utilization rate of the photovoltaic DC breaking device.

With reference to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, the photovoltaic DC disconnection device further includes a sixth switch and a seventh switch;

One end of the sixth switch is connected to the first negative connection end, and the other end of the sixth switch is connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube;

One end of the seventh switch is connected to the third negative connection end, and the other end of the seventh switch is connected to one end of the first switch, the cathode of the second diode, and one end of the gas discharge tube.

It can be known from the sixth possible implementation manner of the first aspect above that, in the photovoltaic DC disconnection device controlling the electrical connection between a plurality of photovoltaic strings and a photovoltaic energy converter, a low voltage specification switching device can also be selected to achieve safety regulations Reliable breaking of approval.

With reference to the fifth or sixth possible implementation manner of the first aspect, in a seventh possible implementation manner, the photovoltaic DC disconnection device further includes an eighth switch and a ninth switch;

The eighth switch is connected between the connection point of the first positive connection terminal and the second positive connection terminal and the cathode of the first diode;

One end of the ninth switch is connected to the third positive connection terminal, and the other end of the ninth switch is connected to the connection point of the third positive connection terminal and the second positive connection terminal and the cathode of the first diode.

It can be known from the seventh possible implementation manner of the first aspect above, that in the photovoltaic DC disconnection device controlling the electrical connection between a plurality of photovoltaic strings and a photovoltaic energy converter, a low-voltage specification switching device can also be selected to achieve safety regulations Reliable breaking of approval.

With reference to the fifth possible implementation manner of the first aspect, in an eighth possible implementation manner, the photovoltaic DC disconnection device further includes a tenth switch and an eleventh switch;

One end of the tenth switch is connected to the first positive connection end, and the other end of the tenth switch is connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube;

One end of the eleventh switch is connected to the third positive connection end, and the other end of the eleventh switch is connected to one end of the first switch, the cathode of the second diode, and one end of the gas discharge tube.

It can be known from the eighth possible implementation manner of the first aspect above, in the photovoltaic DC disconnection device that controls the electrical connection between multiple photovoltaic strings and the photovoltaic energy converter, a low-voltage specification switching device can also be selected to achieve safety regulations Reliable breaking of approval.

With reference to the fifth or eighth possible implementation manner of the first aspect, in a ninth possible implementation manner, the photovoltaic DC disconnection device further includes a twelfth switch and a thirteenth switch;

The twelfth switch is connected between the connection point of the first negative connection terminal and the second negative connection terminal and the cathode of the first diode;

One end of the thirteenth switch is connected to the third negative connection terminal, and the other end of the thirteenth switch is connected to the connection point of the third negative connection terminal and the second negative connection terminal and the anode of the first diode.

It can be known from the ninth possible implementation manner of the first aspect above, in the photovoltaic DC disconnection device that controls the electrical connection between multiple photovoltaic strings and the photovoltaic energy converter, low-voltage specification switching devices can also be selected to achieve safety regulations Reliable breaking of approval.

With reference to the first aspect, in a tenth possible implementation manner, the photovoltaic DC disconnection device further includes a fourth positive connection terminal, a fourth negative connection terminal, a fifth positive connection terminal, a fourteenth switch, and a fifteenth switch. The four positive connection ends and the fourth negative connection ends are used to connect the input end of the third photovoltaic string, and the fifth positive connection end is used to connect the photovoltaic energy converter;

When the first switch, the inverter circuit and the energy absorption circuit are connected in parallel and connected between the first negative connection terminal and the connection point of the second negative connection terminal and the anode of the first diode, the fourth negative connection terminal Connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube, the fourteenth switch is connected at the connection point of the first positive connection end and the second positive connection end and the cathode of the first diode Between, the fifteenth switch is connected between the fourth positive connection terminal and the fifth positive connection terminal.

It can be seen from the tenth possible implementation manner of the first aspect above, in the photovoltaic DC disconnection device that controls the electrical connection between multiple photovoltaic strings and the photovoltaic energy converter, low-voltage specification switching devices can also be selected to achieve safety regulations Reliable breaking of approval.

With reference to the tenth possible implementation manner of the first aspect, in an eleventh possible implementation manner, the photovoltaic DC disconnection device further includes a fourth diode, and a cathode of the fourth diode is connected to the fifteenth Between the switch and the fifth positive terminal, the anode of the fourth diode is connected to the parallel circuit of the first switch, the inverter circuit, and the energy absorption circuit and the second negative Between the connected ends.

With reference to the first aspect, in a twelfth possible implementation manner, the photovoltaic DC disconnection device further includes a sixth positive terminal, a sixth negative terminal, a seventh negative terminal, a fourth diode, and a sixteenth switch And the seventeenth switch, the sixth positive connection terminal and the sixth negative connection terminal are used to connect the input terminal of the fourth photovoltaic string, the seventh negative connection terminal is used to connect the photovoltaic energy converter, and the cathode of the fourth diode is connected Between the parallel circuit of the first switch, the inverter circuit and the energy absorption circuit and the second positive connection terminal, the anode of the fourth diode is connected between one end of the seventeenth switch and the seventh negative connection terminal;

When the first switch, the inverter circuit and the energy absorption circuit are connected in parallel and connected between the first positive connection terminal and the second positive connection terminal, the sixth positive connection terminal is connected to one end of the first switch and the second diode The cathode of the tube is connected to one end of the gas discharge tube, the sixteenth switch is connected between the connection point of the first negative connection terminal and the second negative connection terminal and the anode of the first diode, and the seventeenth switch is connected to the sixth Between the negative connection terminal and the connection point of the seventh negative connection terminal and the anode of the fourth diode.

It can be seen from the twelfth possible implementation manner of the first aspect above, in the photovoltaic DC disconnection device that controls the electrical connection between multiple photovoltaic strings and photovoltaic energy converters, low-voltage specification switching devices can also be selected to achieve safety regulations Reliable breaking on the recognition.

In the above various possible implementation manners, the first diode D1 to the fourth diode D4 may also be the same type of diodes or different types of diodes.

The embodiment of the present application provides that the first diode in the photovoltaic DC disconnection device can make the energy stored in the inductance of the internal direct current (DC) to direct current (DC) circuit of the photovoltaic energy converter go through the bus capacitor to the first diode and return to DC The path of the energy release from the inductance of the DC circuit reduces the energy absorbed by the energy absorption circuit in the photovoltaic DC device, which can reduce the design specifications of the energy absorption circuit. In addition, the energy absorption of the photovoltaic DC breaking device provided in the embodiments of the present application The circuit includes a gas discharge tube, a varistor and a steady-state balancing resistance, wherein the gas discharge tube and the steady-state balancing resistance are connected in parallel, and then connected in series with the varistor, the gas discharge tube is connected in series with the varistor, It can provide the static withstand voltage specification of the energy absorption circuit, thereby reducing the varistor specification; the gas discharge tube series varistor can reduce the instantaneous clamping voltage of the IGBT when it is turned off, thereby reducing the IGBT withstand voltage specification, and realizing the device cost reduction, and Improve the reliability of breaking.

BRIEF DESCRIPTION

1 is a schematic diagram of an example of a breaking device in the prior art;

2 is a schematic diagram of an example of a photovoltaic power station scenario in an embodiment of the present application;

FIG. 3 is another schematic diagram of a photovoltaic power station scenario in an embodiment of the present application;

4 is a schematic diagram of an embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

5 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

6 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

7 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

8 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

9 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

10 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

11 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

12 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

13 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

14 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

15 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

16 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

17 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

18 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

19 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

20 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application;

21 is a schematic diagram of another embodiment of a photovoltaic DC breaking device in an embodiment of the present application.

detailed description

The following describes the embodiments of the present application with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. A person of ordinary skill in the art may know that, with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

The embodiments of the application provide a photovoltaic DC breaking device, which can break the electrical connection between a photovoltaic string and a photovoltaic energy converter at low cost and high reliability. The details will be described below.

The terms "first", "second", "third", etc. in the specification, claims, and drawings of the present application are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence.

FIG. 2 is a schematic diagram of an example of a photovoltaic power station scenario to which a photovoltaic DC breaking device provided by an embodiment of the present application is applied.

As shown in FIG. 2, in the photovoltaic power plant scenario, there will be multiple solar panels, and multiple solar panels are connected in series to form a photovoltaic string. Of course, there are multiple photovoltaic strings shown in FIG. 2 in the photovoltaic power station. Only one photovoltaic string is used as an example for description. The positive pole and the negative pole of the photovoltaic string are respectively connected to the photovoltaic DC breaking device, and the photovoltaic DC breaking device is also connected to the photovoltaic energy converter, so that the photovoltaic DC breaking device can control the electrical circuit between the photovoltaic string and the photovoltaic energy converter Turn on and off. When the photovoltaic energy converter needs maintenance or fails, the electrical line between the photovoltaic string and the photovoltaic energy converter can be quickly disconnected by the photovoltaic DC disconnection device. Figure 2 shows a photovoltaic string connected to a photovoltaic DC disconnection device. In fact, a photovoltaic DC disconnection device can be connected to multiple photovoltaic strings, which can control multiple photovoltaic strings and photovoltaic energy converters. Electrical connection. The photovoltaic energy converter may include an inverter, an optimizer, a direct current to direct current (DC/DC) converter, and a direct current to alternating current (DC/AC) converter.

FIG. 3 is another exemplary schematic diagram of a photovoltaic power station scenario to which the photovoltaic DC breaking device provided by the embodiment of the present application is applied.

As shown in FIG. 3, since the cables of the photovoltaic string have line parasitic inductance, the energy stored in the BST inductance in the internal DC-to-DC circuit of the photovoltaic energy converter also needs to be released, so the photovoltaic DC disconnection device in the embodiment of the present application When cutting off the electrical circuit between the photovoltaic string and the photovoltaic energy converter, it is necessary to control not only the problems of arc drawing, electric shock and ablation, but also to release the energy in the photovoltaic string and the photovoltaic energy converter, thereby effectively Protect the safety and reliability of photovoltaic DC breaking devices.

In order to solve the above problems, as shown in FIG. 4, an embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application may include: a first positive connection end, a first negative connection end, a second positive connection end, and a second negative connection Terminal, first switch K1, first diode D1, converter circuit 10 and energy absorption circuit 20; wherein, the first positive connection terminal and the first negative connection terminal are used to connect the output terminal of the first photovoltaic string, The two positive connection terminals and the second negative connection terminal are used to connect the photovoltaic energy converter.

The first switch K1, the converter circuit 10 and the energy absorption circuit 20 are connected in parallel and connected between the first negative connection terminal and the second negative connection terminal, and the cathode of the first diode D1 is connected to the first positive connection terminal Between the second positive connection terminal, the anode of the first diode D1 is connected between the parallel circuit of the first switch, the inverter circuit, and the energy absorption circuit and the second negative connection terminal.

The inverter circuit 10 includes a first fully controlled semiconductor device Q1, a second fully controlled semiconductor device Q2, a second diode D2 and a third diode D3, wherein the cathode of the second diode D2 is connected to the first fully controlled The input terminal of the semiconductor device Q1 is connected, the anode of the second diode D2 is connected to the output terminal of the first fully controlled semiconductor device Q1 and the output terminal of the second fully controlled semiconductor device Q2, and the anode of the third diode D3 is connected to the first The output terminal of the two fully-controlled semiconductor device Q2 is connected, and the cathode of the third diode D3 is connected to the input terminal of the second fully-controlled semiconductor device Q2.

The energy absorption circuit 20 includes a gas discharge tube G, a steady state balancing resistance R1 and a varistor R2, wherein the gas discharge tube G and the steady state balancing resistance R1 are connected in parallel, and then a varistor is connected in series R2.

In the embodiment corresponding to FIG. 4 above, when the first switch K1 needs to be turned off, the first fully-controlled semiconductor device Q1 and the second fully-controlled semiconductor device Q2 are controlled to be turned on because the first fully-controlled semiconductor device Q1 and the second After the fully-controlled semiconductor device Q2 is turned on, the voltage across the first switch K1 is only about 1-2V. At this time, closing the first switch K1 will not cause arcing and electric ablation of the first switch K1, thereby improving The service life of the first switch K1 is reduced. After the first switch K1 is closed, because the on-resistance of the first switch K1 is very small, usually only a few hundred microohms, most of the current goes from the first switch K1 to the photovoltaic energy converter, thereby reducing the converter circuit 10 Overall loss. Even at this time, the switch tube of the converter circuit 10 can be turned off, so that all the current flows from the first switch K1 to the photovoltaic energy converter.

When it is necessary to turn off the first switch K1, first control the first switch K1 to turn off, so that the breaking voltage of the first switch K1 is reduced to only 1-2V of the conduction voltage drop of the semiconductor device of the converter circuit 10, thereby effectively avoiding In addition to arc drawing and electric shock ablation, the first switch K1 is effectively protected. It is precisely because the solution of the present application can effectively protect the first switch K1, so when selecting the first switch K1, a low-voltage switch specification device can be used It can also economically reduce the cost of photovoltaic DC disconnection devices.

When the first switch K1 is opened, due to the line parasitic inductance of the photovoltaic string cable and the energy stored in the DC-to-DC circuit inductance of the photovoltaic energy converter, the first diode D1 may be used in the embodiment of the present application The energy stored in the DC-to-DC circuit inductance of the photovoltaic energy converter takes the bus capacitor to the first diode D1 and returns to the path of energy release from the DC-to-DC circuit inductance, reducing the energy absorption circuit 20 in the photovoltaic DC-breaking device. The absorbed energy can reduce the design specifications of the energy absorption circuit.

In addition, the parasitic inductance of the line of the photovoltaic string cable is discharged and clamped by the energy absorption circuit 20 in the photovoltaic DC breaking device, and the clamping voltage is ensured not to exceed the specifications of the semiconductor device in the converter circuit 10. The embodiment of the present application In the energy absorption circuit 20 in consideration of the small leakage current of the gas discharge tube G and the large leakage current of the varistor R2, in order to achieve the reliability of the partial pressure, a steady-state balancing resistor R1 is connected in parallel at both ends of the gas discharge tube G to provide a The leakage path makes the voltage on the gas discharge tube G and the varistor R2 not exceed the device specifications. After the gas discharge tube G is connected in parallel with the steady-state balancing resistor R1, it is then connected in series with the varistor R2 to increase the static withstand voltage of the energy absorption circuit 20 through the partial pressure relationship between the gas discharge tube G and the varistor R2, or during gas discharge The parallel steady-state balancing resistors or capacitors or the series/parallel combination of capacitors and resistors on the tube G and the varistor R2 can also achieve this function. When the energy absorption circuit 20 increases rapidly and exceeds the breakdown voltage of the gas discharge tube G, the voltage of the gas discharge tube G will be clamped to a low voltage of tens of volts. At this time, the varistor R2 will act, and the energy absorption at this time The clamping voltage of the circuit 20 is the clamping voltage of the varistor R2 plus the clamping voltage of the gas discharge tube G. It can be seen that the energy absorption circuit 20 provided by the embodiment of the present application can effectively reduce the voltage across the energy absorption circuit 20 The function of low dynamic voltage clamping of the energy absorption circuit 20 is realized, and the use specifications of the varistor R2 in the energy absorption circuit 20 and the semiconductor device in the inverter circuit are reduced.

The specific example of the function of the photovoltaic DC breaking device provided in the embodiment of the present application that can achieve a high static withstand voltage and a low dynamic clamping voltage can be:

If the photovoltaic DC breaking device needs to break the 1000V/10A DC circuit between the photovoltaic string and the photovoltaic energy converter, if the energy absorption circuit only has a varistor, when the DC breaking switch is disconnected, the varistor static withstand voltage at this time Need to meet the specifications of 1000V, considering that the varistor needs to absorb 10A of peak current when the converter circuit is turned off. At this time, the varistor clamping voltage will far exceed 1500V. At this time, the fully controlled semiconductor device in the converter circuit And diode voltage selection will exceed 1500V specifications. The gas discharge tube is connected in series with a varistor. A 750V gas discharge tube can be used in parallel with a steady-state balancing resistor, and then connected in series with a 360V varistor to achieve a static withstand voltage of 1100V to meet the application of 1000V. The converter circuit is turned off At this time, the parasitic inductance energy of the line of the photovoltaic string is released through the converter circuit, and the two voltages of the converter circuit rise rapidly. When the voltage exceeds 1100V, the gas discharge tube G breaks down at this time, the clamping voltage is only about 10V, and the varistor voltage R2 action, in the case of 10A current, the clamping voltage is only about 700V, the clamping voltage of the entire converter circuit 10 does not exceed 800V, and the clamping voltage is low. In this case, the specification of the semiconductor device in the converter circuit 10 only needs 1100V, which can meet the application and effectively reduce the cost of the photovoltaic DC breaking device.

The embodiment corresponding to FIG. 4 described above is the case where the first switch K1, the inverter circuit 10, and the energy absorption circuit 20 are juxtaposed on the first negative connection terminal and the second negative connection terminal. In fact, as shown in FIG. 5, A switch K1, the inverter circuit 10 and the energy absorption circuit 20 may also be connected in parallel to the first positive connection terminal and the second positive connection terminal.

As shown in FIG. 5, an embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application may include: a first positive connection end, a first negative connection end, a second positive connection end, a second negative connection end, and a first switch K1, the first diode D1, the inverter circuit 10 and the energy absorption circuit 20; wherein, the first positive connection terminal and the first negative connection terminal are used to connect the output terminal of the first photovoltaic string, and the second positive connection terminal and The second negative terminal is used to connect the photovoltaic energy converter.

The first switch K1, the inverter circuit 10 and the energy absorption circuit 20 are connected in parallel and connected between the first positive connection terminal and the second positive connection terminal, and the cathode of the first diode D1 is connected to the first positive connection terminal Between the second positive connection terminal, the anode of the first diode D1 is connected between the parallel circuit of the first switch, the inverter circuit and the energy absorption circuit and the second negative connection terminal.

The energy absorption circuit 20 includes a gas discharge tube G, a steady state balancing resistor R1 and a varistor R2, wherein the gas discharge tube G and the steady state balancing resistor R1 are connected in parallel, and then connected in series with the varistor R2.

The function corresponding to the embodiment corresponding to FIG. 5 is the same as the function corresponding to the embodiment corresponding to FIG. 4 except that the first switch K1, the converter circuit 10, and the energy absorption circuit 20 are connected in parallel and connected to the first positive Between the connection end and the second positive connection end.

The embodiments described in FIGS. 4 and 5 above solve the problems of arc drawing and electric shock ablation, and also effectively reduce the specifications of semiconductor devices and varistors, ensuring the safety of photovoltaic DC disconnection devices and reliability. In fact, the safety and reliability of the photovoltaic DC breaking device in the embodiments of the present application can be further improved.

Optionally, as shown in FIG. 6, based on the embodiment corresponding to FIG. 4, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a second switch K2, In the case where the first switch K1, the converter circuit 10, and the energy absorption circuit 20 are connected in parallel and connected between the first negative connection terminal and the second negative connection terminal, one end of the second switch K2 is connected to the first negative connection The second switch K2 is connected to one end of the first switch K1, the cathode of the second diode D2 and one end of the gas discharge tube G.

In fact, the position of the second switch K2 is not limited to the position described in FIG. 6 above, and it may be that one end of the second switch K2 is connected to the second negative connection terminal and the anode of the first diode D1, and the second switch K2 The other end of is connected to one end of the first switch K1, the cathode of the third diode D3 and one end of the varistor R2.

In the embodiment of the present application, the second switch K2 is turned off after the first switch K1. At this time, the converter circuit 10 has been turned off and the energy absorption circuit 20 has high resistance. When the second switch K2 is turned off, there is no voltage and current, so The second switch K2 may use a low-voltage specification switching device to achieve a reliable breaking recognized by safety regulations.

Optionally, as shown in FIG. 7, based on the embodiment corresponding to FIG. 4, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a third switch K3, The third switch K3 is connected between the connection point of the first positive connection terminal and the second positive connection terminal and the cathode of the first diode D1.

In the embodiment of the present application, the third switch K3 is turned off after the first switch K1. At this time, the converter circuit 10 has been turned off, and the energy absorption circuit 20 has high resistance. When the third switch K3 is turned off, there is no voltage and current, so The third switch K3 can use a low-voltage specification switching device to achieve a reliable breaking approved by safety regulations.

Optionally, as shown in FIG. 8, on the basis of the embodiment corresponding to FIG. 6, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a third switch K3, The third switch K3 is connected between the connection point of the first positive connection terminal and the second positive connection terminal and the cathode of the first diode D1.

In the embodiment of the present application, both the second switch K2 and the third switch K3 are turned off after the first switch K1, at this time, the converter circuit 10 has been disconnected, the energy absorption circuit 20 has high resistance, and the second switch K2 and the third switch When K3 is disconnected, there is no voltage and current, so the third switch K3 can use a low-voltage specification switching device to achieve a reliable disconnection recognized by safety regulations.

Optionally, as shown in FIG. 9, based on the embodiment corresponding to FIG. 5, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a fourth switch K4, When the first switch K1, the converter circuit 10 and the energy absorption circuit 20 are connected in parallel and connected between the first positive connection terminal and the second positive connection terminal, one end of the fourth switch K4 is connected to the first positive connection terminal The other end of the fourth switch K4 is connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube.

In fact, the position of the fourth switch K4 is not limited to the situation described in FIG. 9 above. It may also be that one end of the fourth switch K4 is connected to the second positive connection terminal and the cathode of the first diode D1, and the fourth switch K4 The other end of is connected to one end of the first switch K1, the cathode of the third diode D3 and one end of the varistor R2.

In the embodiment of the present application, the fourth switch K4 is turned off after the first switch K1. At this time, the converter circuit 10 has been turned off, and the energy absorption circuit 20 has high resistance. When the fourth switch K4 is turned off, there is no voltage and current, so For the fourth switch K4, a low-voltage specification switching device can be selected to achieve a reliable breaking that is recognized in safety regulations.

Optionally, as shown in FIG. 10, on the basis of the embodiment corresponding to FIG. 5, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a fifth switch K5; The fifth switch K5 is connected between the connection point of the first negative connection terminal and the second negative connection terminal and the anode of the first diode D1.

In the embodiment of the present application, the fifth switch K5 is turned off after the first switch K1. At this time, the converter circuit 10 has been turned off, and the energy absorption circuit 20 has high resistance. When the fifth switch K5 is turned off, there is no voltage and current, so For the fifth switch K5, a low-voltage specification switching device can be selected to achieve a reliable breaking recognized by safety regulations.

Optionally, as shown in FIG. 11, on the basis of the embodiment corresponding to FIG. 9, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a fifth switch K5; The fifth switch K5 is connected between the connection point of the first negative connection terminal and the second negative connection terminal and the anode of the first diode D1.

In the embodiment of the present application, the fourth switch K4 and the fifth switch K5 are opened after the first switch K1, at this time, the converter circuit 10 has been opened, the energy absorption circuit 20 is high-impedance, and the fourth switch K4 and the fifth switch K5 There is no voltage or current when it is disconnected, so the fifth switch K5 can use a low-voltage specification switching device to achieve a reliable disconnection recognized by safety regulations.

The photovoltaic DC disconnection devices described in the above multiple embodiments only illustrate the case of two positive connection ends and two negative connection ends. In fact, a photovoltaic DC disconnection device may include multiple positive connection ends and multiple negative connection ends Connection end. As shown in FIGS. 12 and 13, the photovoltaic DC breaking device may further include a third positive connection end and a third negative connection end, the third negative connection end is connected between the first negative connection end and the second negative connection end, The third positive connection end is connected between the first positive connection end and the second positive connection end, and the third positive connection end and the third negative connection end are used to connect the second photovoltaic string.

As shown in FIG. 12, on the basis of the embodiment corresponding to FIG. 4, a third positive connection terminal and a third negative connection terminal are added. The third negative connection terminal is connected to the first negative connection terminal and the first switch, Between the three parallel circuits of the commutation circuit and the energy absorption circuit, the third positive connection terminal is connected between the first positive connection terminal and the second positive connection terminal and the connection point of the cathode of the first diode D1, The third positive connection terminal and the third negative connection terminal are used to connect the input terminal of the second photovoltaic string.

As shown in FIG. 13, on the basis of the embodiment corresponding to FIG. 5, a third positive connection terminal and a third negative connection terminal are added. The third negative connection terminal is connected to the first negative connection terminal and the first switch, Between the three parallel circuits of the commutation circuit and the energy absorption circuit, the third positive connection terminal is connected between the first positive connection terminal and the second positive connection terminal and the connection point of the cathode of the first diode D1, The third positive connection terminal and the third negative connection terminal are used to connect the input terminal of the second photovoltaic string.

In the embodiments corresponding to FIGS. 12 and 13, the third positive connection end and the third negative connection end are used to connect the input end of the second photovoltaic string, indicating that the second photovoltaic string can be shared with the first photovoltaic string A photovoltaic DC breaking device is used for breaking control between photovoltaic string and photovoltaic energy converter. The voltage and current of the second photovoltaic string are delivered to the photovoltaic energy converter through the second positive connection end and the second negative connection end of the photovoltaic DC disconnection device.

The control principle of two or more photovoltaic strings sharing a photovoltaic DC breaking device to break the photovoltaic string and the photovoltaic energy converter is the same as the principle described in the foregoing embodiment, and the details will not be described in detail .

Optionally, on the basis of the above embodiment corresponding to FIG. 12, as shown in FIG. 14, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a sixth switch K6 And the seventh switch K7, one end of the sixth switch K6 is connected to the first negative connection end, the other end of the sixth switch K6 is connected to one end of the first switch K1, the cathode of the second diode D2 and one end of the gas discharge tube G One end of the seventh switch K7 is connected to the third negative connection end, and the other end of the seventh switch K7 is connected to one end of the first switch K1, the cathode of the second diode D2 and one end of the gas discharge tube G.

In the embodiment of the present application, regardless of controlling the DC circuit between the first photovoltaic string and the photovoltaic energy converter or the DC circuit between the second photovoltaic string and the photovoltaic energy converter, the sixth switch K6 or the seventh switch K7 Both are turned off after the first switch K1, the converter circuit 10 has been turned off, the energy absorption circuit 20 has high resistance, and the sixth switch K6 or the seventh switch K7 has no voltage and current when turned off, so the sixth switch K6 Or the seventh switch K7 can use low-voltage specification switching devices to achieve a reliable breaking approved by safety regulations.

Optionally, on the basis of the above embodiment corresponding to FIG. 12, as shown in FIG. 15, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes an eighth switch K8 And the ninth switch K9; the eighth switch K8 is connected between the first positive connection terminal and the second positive connection terminal and the connection point of the cathode of the first diode D1; one end of the ninth switch K9 is connected to the third positive connection terminal The other end of the ninth switch K8 is connected to the connection point of the third positive connection terminal and the second positive connection terminal and the cathode of the first diode D1.

In the embodiment of the present application, whether controlling the DC circuit between the first photovoltaic string and the photovoltaic energy converter or the DC circuit between the second photovoltaic string and the photovoltaic energy converter, the eighth switch K8 or the ninth switch K9 Both are disconnected after the first switch K1, the converter circuit 10 has been disconnected, the energy absorption circuit 20 has high resistance, the eighth switch K8 or the ninth switch K9 has no voltage and current when it is turned off, so the eighth switch K8 Or the ninth switch K9 can use low-voltage specification switching devices to achieve a reliable breaking approved by safety regulations.

Optionally, on the basis of the above embodiment corresponding to FIG. 14, as shown in FIG. 16, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes an eighth switch K8 And the ninth switch K9; the eighth switch K8 is connected between the first positive connection terminal and the second positive connection terminal and the connection point of the cathode of the first diode D1; one end of the ninth switch K9 is connected to the third positive connection terminal The other end of the ninth switch K8 is connected to the connection point of the third positive connection terminal and the second positive connection terminal and the cathode of the first diode D1.

In the embodiment of the present application, regardless of controlling the DC circuit between the first photovoltaic string and the photovoltaic energy converter or the DC circuit between the second photovoltaic string and the photovoltaic energy converter, the sixth switch K6 and the seventh switch K7 , The eighth switch K8 or the ninth switch K9 are turned off after the first switch K1, at this time the converter circuit 10 has been disconnected, the energy absorption circuit 20 is high impedance, the sixth switch K6, the seventh switch K7, the eighth switch K8 or the ninth switch K9 has no voltage and current when it is turned off, so the sixth switch K6, the seventh switch K7, the eighth switch K8 or the ninth switch K9 can use low voltage specification switching devices to achieve the reliability of safety approval Break.

In addition, it should be noted that FIGS. 17-19 are illustrated by connecting two sets of photovoltaic strings as an example. In actual applications, multiple sets of photovoltaic strings can be connected according to requirements. When multiple sets of photovoltaic strings are connected The principle of FIG. 17 is basically the same as the principle of FIG. 17 to FIG. 19 described above. In the embodiment of the present application, no more details will be given for the case of accessing 3 or more photovoltaic strings.

Optionally, on the basis of the above embodiment corresponding to FIG. 13, as shown in FIG. 17, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a tenth switch K10 And the eleventh switch K11, one end of the tenth switch K10 is connected to the first positive connection end, the other end of the tenth switch K10 is connected to one end of the first switch K1, the cathode of the second diode D2 and the gas discharge tube G One end is connected; one end of the eleventh switch K11 is connected to the third positive connection end, the other end of the eleventh switch K11 is connected to one end of the first switch K1, the cathode of the second diode D2 and one end of the gas discharge tube G .

In the embodiment of the present application, no matter whether the DC circuit between the first photovoltaic string and the photovoltaic energy converter is controlled or the DC circuit between the second photovoltaic string and the photovoltaic energy converter, the tenth switch K10 or the eleventh switch K11 is disconnected after the first switch K1, at this time the converter circuit 10 has been disconnected, the energy absorption circuit 20 has high resistance, the tenth switch K10 or the eleventh switch K11 has no voltage and current when it is turned off, so the tenth The switch K10 or the eleventh switch K11 can use a low-voltage specification switching device to achieve a reliable breaking approved by safety regulations.

Optionally, on the basis of the above embodiment corresponding to FIG. 13, as shown in FIG. 18, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a twelfth switch K12 and the thirteenth switch K13, the twelfth switch K12 is connected between the first negative connection terminal and the connection point of the second negative connection terminal and the cathode of the first diode D1, one end of the thirteenth switch K13 is connected to the Three negative terminals, the other end of the thirteenth switch K13 is connected to the connection point of the third negative terminal and the second negative terminal and the anode of the first diode D1.

In the embodiment of the present application, no matter whether the DC circuit between the first photovoltaic string and the photovoltaic energy converter is controlled or the DC circuit between the second photovoltaic string and the photovoltaic energy converter, the twelfth switch K12 or the thirteenth The switches K13 are all disconnected after the first switch K1. At this time, the converter circuit 10 has been disconnected, the energy absorption circuit 20 has high resistance, and there is no voltage and current when the twelfth switch K12 or the thirteenth switch K13 is turned off, so For the twelfth switch K12 or the thirteenth switch K13, low-voltage specification switching devices can be selected to achieve a reliable disconnection approved by safety regulations.

Optionally, on the basis of the above embodiment corresponding to FIG. 17, as shown in FIG. 19, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a twelfth switch K12 and the thirteenth switch K13, the twelfth switch K12 is connected between the first negative connection terminal and the connection point of the second negative connection terminal and the cathode of the first diode D1, one end of the thirteenth switch K13 is connected to the Three negative terminals, the other end of the thirteenth switch K13 is connected to the connection point of the third negative terminal and the second negative terminal and the anode of the first diode D1.

In the embodiment of the present application, the tenth switch K10 and the eleventh switch no matter whether the DC circuit between the first photovoltaic string and the photovoltaic energy converter is controlled or the DC circuit between the second photovoltaic string and the photovoltaic energy converter is controlled K11, the twelfth switch K12 or the thirteenth switch K13 are all disconnected after the first switch K1, at this time the converter circuit 10 has been disconnected, the energy absorption circuit 20 is high resistance, the tenth switch K10, the eleventh switch K11 , The twelfth switch K12 or the thirteenth switch K13 has no voltage and current when it is turned off, so the tenth switch K10, the eleventh switch K11, the twelfth switch K12 or the thirteenth switch K13 can use low voltage specification switches The device realizes the reliable breaking of safety approval.

The solutions of the multiple positive connection terminals and the multiple negative connection terminals provided in the above FIGS. 12 to 19 are all connected internally by the photovoltaic DC disconnection device, such as the first positive connection terminal and the first negative connection terminal and the first The three positive connection terminal and the third negative connection terminal share the second positive connection terminal and the second negative connection terminal on the photovoltaic energy converter side. In fact, in the embodiment provided by the present application, it is not limited that the first positive connection end and the first negative connection end and the third positive connection end and the third negative connection end share a second positive on the photovoltaic energy converter side The connection terminal and the second negative connection terminal.

In addition, it should be noted that FIGS. 17-19 are illustrated by connecting two sets of photovoltaic strings as an example. In actual applications, multiple sets of photovoltaic strings can be connected according to requirements. When multiple sets of photovoltaic strings are connected The principle of FIG. 12 is basically the same as the principle of FIGS. 12 to 16 described above. In the embodiment of the present application, no more details will be given for the case of accessing 3 or more photovoltaic strings.

Optionally, on the basis of the embodiment corresponding to FIG. 4 described above, as shown in FIG. 20, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a fourth positive The connection terminal, the fourth negative connection terminal, the fifth positive connection terminal, the fourteenth switch K14 and the fifteenth switch K15, the fourth positive connection terminal and the fourth negative connection terminal are used to connect the input terminal of the third photovoltaic string, The fifth positive connection terminal is used to connect the photovoltaic energy converter; when the first switch K1, the converter circuit 10 and the energy absorption circuit 20 are connected in parallel, and connected to the first negative connection terminal and the second negative connection terminal and the first Between the connection points of the anode of a diode D1, the fourth negative connection end is connected to one end of the first switch K1, the cathode of the second diode D2 and one end of the gas discharge tube G, and the fourteenth switch K14 is connected Between the connection point of the first positive connection terminal and the second positive connection terminal and the cathode of the first diode D1, the fifteenth switch K15 is connected between the fourth positive connection terminal and the fifth positive connection terminal.

In the embodiment of the present application, the fifth positive connection terminal is not connected to the second positive connection terminal in the photovoltaic DC disconnection device, but in the photovoltaic energy converter, the fifth positive connection terminal can be realized by a circuit in the photovoltaic energy converter The second positive connection terminal is connected, so that the line between the fourth positive connection terminal and the fifth positive connection terminal can also effectively utilize the first diode D1, the inverter circuit 10, and the energy absorption circuit 20.

In the embodiments of the present application, whether the DC circuit between the first photovoltaic string and the photovoltaic energy converter is controlled or the DC circuit between the third photovoltaic string and the photovoltaic energy converter, the fourteenth switch K14 or the fifteenth switch Both K15 are turned off after the first switch K1. At this time, the converter circuit 10 has been turned off, and the energy absorption circuit 20 has high resistance. The fourteenth switch K14 or the fifteenth switch K15 has no voltage and current when turned off, so the first The fourteenth switch K14 or the fifteenth switch K15 can use low-voltage specification switching devices to achieve a reliable breaking approved by safety regulations.

In fact, on the basis of the solution described in FIG. 20 above, the photovoltaic DC disconnection device may further include a fourth diode whose cathode is connected to the fifteenth switch K15 and the fifth positive Between the connection terminals, the anode of the fourth diode is connected between the parallel circuit of the first switch, the inverter circuit, and the energy absorption circuit and the second negative connection terminal.

Optionally, on the basis of the above embodiment corresponding to FIG. 5, as shown in FIG. 21, in another embodiment of the photovoltaic DC breaking device provided by the embodiment of the present application, the photovoltaic DC breaking device further includes a sixth positive The connection terminal, the sixth negative connection terminal, the seventh negative connection terminal, the fourth diode D4, the sixteenth switch K16 and the seventeenth switch K17, the sixth positive connection terminal and the sixth negative connection terminal are used to connect the fourth The input terminal of the photovoltaic string, the seventh negative connection terminal is used to connect the photovoltaic energy converter, and the cathode of the fourth diode D4 is connected to the first switch K1, the inverter circuit and the energy absorption circuit. The parallel circuit and the second positive Between the connection terminals, the anode of the fourth diode D4 is connected between one end of the seventeenth switch K17 and the seventh negative connection terminal; when the first switch K1, the converter circuit 10 and the energy absorption circuit 20 are connected in parallel, And connected between the first positive connection end and the second positive connection end, the sixth positive connection end is connected to the end of the first switch K1, the cathode of the second diode D2 and the end of the gas discharge tube G, the tenth The six switches K16 are connected between the first negative connection terminal and the second negative connection terminal and the connection point of the anode of the first diode D1, and the seventeenth switch K17 is connected between the sixth negative connection terminal and the seventh negative connection terminal Between the connection points of the anode of the fourth diode.

In the embodiment of the present application, the fourth diode D2 is introduced, so that the DC line between the sixth negative connection terminal and the seventh negative connection terminal can also directly use the first switch K1 and the converter circuit inside the photovoltaic DC disconnection device 10 and the energy absorption circuit 20, so that the DC circuit between the fourth photovoltaic string connected to the sixth positive connection end, the sixth negative connection end and the seventh negative connection end and the photovoltaic energy converter can be safely and reliably performed Break.

In the embodiments of the present application, whether the DC circuit between the first photovoltaic string and the photovoltaic energy converter is controlled or the DC circuit between the fourth photovoltaic string and the photovoltaic energy converter, the sixteenth switch K16 or the seventeenth switch Both K17 are disconnected after the first switch K1. At this time, the converter circuit 10 has been disconnected, and the energy absorption circuit 20 has high resistance. The sixteenth switch K16 or the seventeenth switch K17 has no voltage and current when it is turned off. The sixteen switch K16 or the seventeenth switch K17 can use low-voltage specification switching devices to achieve a reliable disconnection recognized by safety regulations.

The above lists the possible embodiments of the photovoltaic DC disconnection device in the embodiments of the present application in many different situations, but in fact the solutions that can be included in the present application are not limited to the above-listed embodiments, other based on the principles of the present application Circuit deformations are within the scope of protection of this application.

In addition, in the above embodiments, the first switch K1 to the seventeenth switch K17 are used. In fact, these switches can be the same type of switch or different types of switches, and these switches can be relays. , Any device or combination of circuit breakers, contactors, electromagnetic mechanical switches.

In addition, it should be noted that the above use of the first positive connection terminal, the first negative connection terminal to the sixth positive connection terminal, the seventh negative connection terminal, and other first switches K1 to the seventeenth switch K17, the first second The diode D1 to the fourth diode D4, the first fully-controlled semiconductor device Q1, and the second fully-controlled semiconductor device Q2 are only used to distinguish similar objects, and need not be used to describe a specific order or sequence.

The photovoltaic DC breaking device provided by the embodiments of the present application has been described in detail above, and specific examples are used to explain the principles and implementation of the present application. The descriptions of the above embodiments are only used to help understand the method and the application of the present application. The core idea; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation and scope of application. In summary, the content of this specification should not be understood as limit.

Claims

A photovoltaic DC breaking device is characterized by comprising:

The first positive connection terminal, the first negative connection terminal, the second positive connection terminal, the second negative connection terminal, the first switch, the first diode, the converter circuit and the energy absorption circuit;

Wherein, the first positive connection end and the first negative connection end are used to connect the output end of the first photovoltaic string, and the second positive connection end and the second negative connection end are used to connect photovoltaic energy conversion Device

The first switch, the converter circuit, and the energy absorption circuit are connected in parallel and connected between the first negative connection terminal and the second negative connection terminal. The cathode is connected between the first positive terminal and the second positive terminal, and the anode of the first diode is connected to the first switch, the inverter circuit and the energy absorption circuit. Between the parallel circuit and the second negative connection; or, the first switch, the converter circuit, and the energy absorption circuit are connected in parallel between the first positive connection and the second Between the positive connection terminals, the cathode of the first diode is connected between the parallel circuit of the first switch, the inverter circuit, and the energy absorption circuit and the second positive connection terminal. An anode of the first diode is connected between the first negative connection terminal and the second negative connection terminal;

The inverter circuit includes a first fully-controlled semiconductor device, a second fully-controlled semiconductor device, a second diode and a third diode, wherein the cathode of the second diode and the first fully-controlled The input terminal of the semiconductor device is connected, the anode of the second diode is connected to the output terminal of the first fully controlled semiconductor device and the output terminal of the second fully controlled semiconductor device, and the An anode is connected to the output end of the second fully controlled semiconductor device, and a cathode of the third diode is connected to the input end of the second fully controlled semiconductor device;

The energy absorption circuit includes a gas discharge tube, a varistor, and a steady-state balancing resistance, wherein the gas discharge tube and the steady-state balancing resistance are connected in parallel, and then connected in series with the varistor.
The photovoltaic DC breaking device according to claim 1, wherein the photovoltaic DC breaking device further comprises a second switch;

In the case where the first switch, the converter circuit, and the energy absorption circuit are connected in parallel and connected between the first negative connection terminal and the second negative connection terminal, the second One end of the switch is connected to the first negative connection end, and the other end of the second switch is connected to one end of the first switch, the cathode of the second diode, and one end of the gas discharge tube, or One end of the second switch is connected to the second negative connection terminal and the anode of the first diode, and the other end of the second switch is connected to one end of the first switch and the third diode The cathode of the tube is connected to one end of the varistor.
The photovoltaic DC breaking device according to claim 1 or 2, wherein the photovoltaic DC breaking device further comprises a third switch;

The third switch is connected between the connection point of the first positive connection terminal and the second positive connection terminal and the cathode of the first diode.
The photovoltaic DC breaking device according to claim 1, wherein the photovoltaic DC breaking device further comprises a fourth switch;

When the first switch, the inverter circuit and the energy absorption circuit are connected in parallel and connected between the first positive connection terminal and the second positive connection terminal, the One end is connected to the first positive connection end, and the other end of the fourth switch is connected to one end of the first switch, the cathode of the second diode, and one end of the gas discharge tube, or One end of the fourth switch is connected to the second positive connection terminal and the cathode of the first diode, and the other end of the fourth switch is connected to one end of the first switch and the third diode The cathode is connected to one end of the varistor.
The photovoltaic DC breaking device according to claim 1 or 4, wherein the photovoltaic DC breaking device further comprises a fifth switch;

The fifth switch is connected between the connection point of the first negative connection terminal and the second negative connection terminal and the anode of the first diode.
The photovoltaic DC breaking device according to claim 1, wherein the photovoltaic DC breaking device further comprises a third positive connection end and a third negative connection end;

The third negative connection terminal is connected between the first negative connection terminal and the first switch, the inverter circuit, and the energy absorption circuit in parallel, and the third positive connection terminal is connected at Between the first positive connection terminal and the connection point of the second positive connection terminal and the cathode of the first diode, the third positive connection terminal and the third negative connection terminal are used to connect the first The input end of two photovoltaic strings.
The photovoltaic DC breaking device according to claim 6, wherein the photovoltaic DC breaking device further includes a sixth switch and a seventh switch;

One end of the sixth switch is connected to the first negative connection end, and the other end of the sixth switch is connected to one end of the first switch, the cathode of the second diode and the gas discharge tube One end connected

One end of the seventh switch is connected to the third negative connection terminal, the other end of the seventh switch is connected to one end of the first switch, the cathode of the second diode, and the gas discharge tube One end is connected.
The photovoltaic DC breaking device according to claim 6 or 7, wherein the photovoltaic DC breaking device further includes an eighth switch and a ninth switch;

The eighth switch is connected between the connection point of the first positive connection terminal and the second positive connection terminal and the cathode of the first diode;

One end of the ninth switch is connected to the third positive connection terminal, and the other end of the ninth switch is connected to the third positive connection terminal and the second positive connection terminal and the first diode On the connection point of the cathode.
The photovoltaic DC breaking device according to claim 6, wherein the photovoltaic DC breaking device further comprises a tenth switch and an eleventh switch;

One end of the tenth switch is connected to the first positive connection end, the other end of the tenth switch is connected to one end of the first switch, the cathode of the second diode and the gas discharge tube One end connected

One end of the eleventh switch is connected to the third positive connection end, and the other end of the eleventh switch is connected to one end of the first switch, the cathode of the second diode, and the gas discharge One end of the tube is connected.
The photovoltaic DC breaking device according to claim 6 or 9, wherein the photovoltaic DC breaking device further comprises a twelfth switch and a thirteenth switch;

The twelfth switch is connected between the connection point of the first negative connection terminal and the second negative connection terminal and the cathode of the first diode;

One end of the thirteenth switch is connected to the third negative connection terminal, and the other end of the thirteenth switch is connected to the third negative connection terminal and the second negative connection terminal and the first two-pole The connection point of the anode of the tube.
The photovoltaic DC breaking device according to claim 1, wherein the photovoltaic DC breaking device further comprises a fourth positive connecting terminal, a fourth negative connecting terminal, a fifth positive connecting terminal, a fourteenth switch and a fifteenth switch , The fourth positive connection end and the fourth negative connection end are used to connect the input end of the third photovoltaic string, and the fifth positive connection end is used to connect the photovoltaic energy converter;

When the first switch, the commutation circuit and the energy absorption circuit are connected in parallel and connected to the first negative connection terminal and the second negative connection terminal and the anode of the first diode Between the connection points, the fourth negative connection end is connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube, and the fourteenth switch is connected at Between the first positive connection terminal and the connection point of the second positive connection terminal and the cathode of the first diode, the fifteenth switch is connected between the fourth positive connection terminal and the first Between five positive connecting ends.
The photovoltaic DC breaking device according to claim 11, wherein the photovoltaic DC breaking device further comprises a fourth diode, a cathode of the fourth diode is connected to the fifteenth switch and the first Between the five positive terminals, the anode of the fourth diode is connected between the parallel circuit of the first switch, the inverter circuit, and the energy absorption circuit and the second negative terminal.
The photovoltaic DC breaking device according to claim 1, wherein the photovoltaic DC breaking device further comprises a sixth positive connecting terminal, a sixth negative connecting terminal, a seventh negative connecting terminal, a fourth diode, a sixteenth A switch and a seventeenth switch, the sixth positive connection terminal and the sixth negative connection terminal are used to connect the input terminal of the fourth photovoltaic string, and the seventh negative connection terminal is used to connect the photovoltaic energy converter , The cathode of the fourth diode is connected between the parallel circuit of the first switch, the inverter circuit, and the energy absorption circuit and the second positive connection terminal, and the fourth diode The anode of the tube is connected between one end of the seventeenth switch and the seventh negative connection end;

When the first switch, the converter circuit and the energy absorption circuit are connected in parallel and connected between the first positive connection terminal and the second positive connection terminal, the sixth positive connection Is connected to one end of the first switch, the cathode of the second diode and one end of the gas discharge tube, and the sixteenth switch is connected to the first negative connection end and the second negative Between the connection terminal and the connection point of the anode of the first diode, the seventeenth switch is connected between the sixth negative connection terminal and the seventh negative connection terminal and the fourth diode Between the connection points of the anode.